Flexible curtain rollup door with combination stiffening struts and windlocks

ABSTRACT

A flexible curtain rollup door includes a drum mounted on a door frame and drivenly connected to an electric right angle gear motor unit. The frame includes opposed channel shaped guide tracks for receiving opposed side edges of a door curtain. Spaced apart elastically deflectable combination curtain stiffening struts and windlock members are secured to the curtain and include opposed windlock parts receivable in the guide tracks and configured, respectively, to provide for releasing only one side edge of the curtain from its guide track. A flexible transverse bottom bar includes plural side by side flexible bags filled with particulate material, secured to the curtain bottom edge and enclosed by a flexible envelope member. The curtain bottom edge includes a stiffener formed of interconnected links.

BACKGROUND OF THE INVENTION

[0001] Rollup type doors are widely used in many applications forforming a closure over an opening in a building. Rollup type doors aretypically characterized by flexible curtain-like closure members whichare adapted to be wound onto a rotatable drum for moving the doorbetween a closed position and an open position. Flexible curtain rollupdoors do, however, require reinforcement to prevent windloads fromblowing the curtain out of opposed guide tracks or channels and throughthe door opening. Such re-inforcements may include plural spaced apartwindlock members disposed above the curtain edges, a thickened portionof the opposed edges of the curtain or one or more spaced apartlaterally extending windbar members disposed adjacent to the doorcurtain and guided in opposed guide tracks.

[0002] However, in many industrial applications of rollup type doors itis also desirable: to provide for releasing the aforementioned windbarsor windlocks under impact loads which are often encountered by suchdoors being impacted by freight-moving vehicles, such as lift trucks,for example. Moreover, such doors are also desirably adapted to releasefrom opposed door edge guides at a predetermined air pressuredifferential or “windload” to prevent catastrophic failure of the doorand its associated support structure. Flexible curtain type doors havebeen developed which include windbars or windlocks at opposite lateraledges of the door which provide for completely releasing the door fromits opposed guides. However, releasing the door at both side edges fromthe associated guide structure complicates the requirements forreinserting the door curtain in the guide tracks. Still further, certainprior art doors which are provided with side edge windlocks and also areprovided with laterally extending reinforcing or stiffening members.,often called windbars, are somewhat complicated.

[0003] Various other desiderata have been recognized in industrialrollup doors including improvements in the door bottom edge seal, or socalled bottom bar, wherein it is desirable to provide weightingstructure operable to assist in pulling the door toward a closedposition while at the same time configuring the weighting structure sothat it will not damage an object upon which the door may inadvertentlyclose.

[0004] Still further, it is desirable to provide an uncomplicated andinexpensive design which still meets all of the desiderata andtrouble-free operation for rollup type doors. It is to these ends thatthe present invention has been developed.

SUMMARY OF THE INVENTION

[0005] The present invention provides an improved flexible curtain typedoor and an improved rollup flexible type door, in particular, andwherein the door is operable to maintain a closure over an opening undersubstantial windloads while also providing for release of the doorcurtain at one side should forces acting on the curtain be excessive andpotentially damaging.

[0006] In accordance with one aspect of the invention, a flexiblecurtain type door is provided with combination curtain stiffening strutsor battens and windlocks which are operable to release the curtain alongat least one of the curtain side edges from curtain side edge guidestructure. In particular, the combination struts and windlocks arepreferably operable to release the door curtain at only one lateral sidethereof to minimize the requirements of resetting the curtain within theguides while providing sufficient relief from forces acting on the doorwhich would otherwise possibly damage the curtain and/or associated doorguide structure.

[0007] The present invention also provides an improved curtain and strutguide track section which includes opposed recapture chutes and movableguide track parts which provide guidance for the curtain and strut edgesduring normal operation of the door but also allow reentry or recaptureof the curtain and strut edges if the curtain has been displaced fromthe guide tracks in either one of opposite directions.

[0008] Still further, there is provided a flexible curtain type door,particularly adapted for operation as a rollup door and which includesan improved bottom edge or so-called bottom bar assembly includingcurtain stiffening members which provide stiffness in oppositedirections out of the normal plane of the door curtain but allowdeflection in a vertical direction generally in the plane of the door.The invention still further includes a simplified and advantageous motordrive arrangement for rotating a drum on which a door curtain is woundwhen moving the curtain between open and closed positions.

[0009] Those skilled in the art will further appreciate theabove-mentioned advantages and superior features of the flexible curtaindoor of the present invention together with other important aspectsthereof upon reading the detailed description which follows inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a front elevation view of a flexible curtain type doorin accordance with the present invention;

[0011]FIG. 2 is a section view taken generally along the line 2-2 ofFIG. 1;

[0012]FIG. 3 is a side elevation of the door assembly shown in FIGS. 1and 2;

[0013]FIG. 4 is an exploded perspective view showing a preferredarrangement of a drive motor and curtain drum for the door assembly ofthe present invention;

[0014]FIG. 5A is a perspective view of a portion of one preferredembodiment of a curtain bottom bar assembly in accordance with thepresent invention;

[0015]FIG. 5B is a section view taken along the line 5B-5B of FIG. 5A;

[0016]FIG. 6 is a detail view showing one preferred embodiment of adevice for recapturing one end of respective combination struts andwindlocks within the guide track for the door assembly of the presentinvention;

[0017]FIG. 7 is a side elevation of one preferred embodiment of acombination strut and associated windlock members of the presentinvention;

[0018]FIG. 8 is a detail section view taken generally along the line 2-2but on a larger scale than the view of FIG. 2;

[0019]FIG. 9 is a detail view of one end of a combination strut andwindlock member showing a configuration which permits release of thewindlock portion of the strut from its guide track;

[0020]FIG. 10 is an end view of the combination strut and windlock partsshown in FIGS. 7 through 9 illustrating the profile thereof;

[0021]FIG. 11 is a detail view showing how the combination strut andwindlock member of the embodiment of FIGS. 7 through 9 are releasablefrom their associated guide track at one side of the door curtain;

[0022]FIG. 12 is a detail view showing how the combination strut andwindlock members of the embodiment of FIGS. 7 through 9 are retained inthe opposite guide track even when substantially deflected;

[0023]FIG. 13 is a plan view of an alternate embodiment of a combinationstiffening strut and windlocks in accordance with the present invention;

[0024]FIG. 14 is a side elevation of the strut shown in FIG. 13;

[0025]FIG. 15 is a detail section view showing one end of the strut ofFIGS. 13 and 14 deflected but retained in the guide track;

[0026]FIG. 16 is a detail section view of the opposite end of the strutshown in FIGS. 13 and 14 being pulled out of its guide track at acertain amount of deflection;

[0027]FIG. 17 is a perspective view of an alternate embodiment of acurtain side edge and strut recapture device;

[0028]FIG. 18 is a detail section view taken from the line 18-18 of FIG.19; and

[0029]FIG. 19 is a perspective view of an alternate embodiment of abottom bar assembly for a flexible curtain rollup door in accordancewith the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0030] In the description which follows like parts are marked throughoutthe specification and drawing with the same reference numerals,respectively. The drawing figures are not necessarily to scale andcertain features may be shown in somewhat generalized form in theinterest of clarity and conciseness.

[0031] Referring to FIGS. 1, 2, and 3, there is illustrated an improvedflexible curtain type rollup door assembly in accordance with theinvention and generally designated by the numeral 20. The rollup doorassembly 20 is characterized by a substantially planar, flexible curtainclosure member 22 supported by and adapted to be rolled on and off of arotatable drum 24 for forming a closure over a door opening 26 formed ina wall 28, see FIGS. 1 and 2.

[0032] The door assembly 20 is further characterized by opposedelongated guide track support members 30 and 32, characterized asconventional right angle structural members and which are adapted to fitwithin the door opening 26, and suitably secured to the wall 28, asshown in FIG. 2. The support members 30 and 32 are adapted to support.,respectively, spaced apart headplate members 34 and 36, FIGS. 1, 3, and4 which are secured to the members 30 and 32 by conventional mechanicalfasteners, not shown in FIGS. 1 and 3. The headplate members 34 and 36are adapted to support the roller or drum 24, which includes anelongated central shaft 25, see FIG. 4, projecting from opposite sidesof a drum member 27 and supported in spaced apart bearings 29, one shownin FIG. 4. Bearings 29 are, respectively, suitably secured to theopposed headplate members 34 and 36.

[0033] As shown in FIGS. 1, 3, and 4, the door assembly 20 isadvantageously provided with a drive motor unit 38 comprising acommercially available electric drive motor 38 a drivably connected to aright angle gear drive unit 40, FIG. 4. Gear drive unit 40 includes ahollow, rotatable output shaft 42 supported thereon which is adapted toreceive the distal end 25 a of shaft 25 in a suitable driving connectiontherewith. Drive motor unit 38 is adapted to be mounted on headplate 36by way of an intermediate mounting plate 37, FIG. 4, and by conventionalmechanical fasteners 41, as shown in the exploded perspective view ofFIG. 4. One advantage of the commercially available drive motor unit 38is the compact and reduced space requirement configuration of the motor,as indicated by drawing FIGS. 1, 3, and 4. In other words, by providinga right angle drive between the motor output shaft 38 b and the axis ofrotation 24 a of the roller or drum 24 and its shaft 25 the spacerequirements for the drive motor for the door assembly 20 aresubstantially reduced. One commercial source for the drive motor unit 38is Sumitomo Machinery Corporation of America as their type SM-Hyponic.Drive motor units 38 of from 0.50 hp to 3.0 hp are suitable for doorassemblies 20 of from about five feet to twenty four feet height andfour feet to twenty six feet width. The fabric of the curtain 22 ispreferably 1.0 to 2.50 millimeter thick polyvinyl chloride withinterwoven fabric reinforcement.

[0034] Referring further to FIGS. 1, 3, and 5A, the door curtain 22 isprovided with a so called soft transverse bottom bar assembly 42,normally operable to form a seal at a floor surface 28 a, FIG. 1, whenthe door 20 is in a closed position. The bottom bar assembly 42 isadapted to minimize damage to any object which may be disposed in thedoorway when the door curtain 22 is moved to the door closed position.As shown in FIGS. 1, 5A and 5B, the bottom bar assembly 42 ischaracterized by plural flexible bag-like members 44 mountedside-by-side substantially across the width of the curtain 22, and withadjacent members 44 mounted substantially contiguous with each other. Asshown in FIG. 5B, the bottom bar bag members 44 are preferably filledwith a particulate material, such as steel shot, welding slag, sand orother relatively dense particulate material, indicated by numeral 46 inFIG. 5B.

[0035] Each bag member 44 is also, preferably contained within an outer,flexible envelope member 45 preferably closed by heat sealing, forexample, at its opposite ends. Each of the bags 44 and each envelopemember 45 may, preferably, be formed of a suitable flexible material,such as the material used for the curtain 22. Each bag and envelope 44,45 is attached to the curtain 22 adjacent curtain bottom edge 22 e byfastener means comprising plural spaced apart aluminum rivets 51 andrivet grommets 51 a, as shown in FIGS. 5A and 5B. In particular, rivets51 secure the bag envelopes 45 to the curtain 22, as shown.

[0036] By providing plural bags 44 mounted side by side across thetransverse bottom edge 22 e of curtain 22, firmness yet flexibility ofthe bottom bar assembly 42 is provided for conforming to the shape ofany obstruction which might be encountered by the bottom bar assembly asthe curtain 22 is moved to a closed position. Moreover, provision ofplural side-by-side mounted bag members 44 alleviates the tendency forthe particulate material 46 to gravitate to one side or the other of thedoor curtain 22 as might occur if the soft bottom bar assembly 42 wasformed with a single bag or receptacle for all of the particulatematerial 46.

[0037] Added protection for the soft bottom bar bags 44 is provided byan outer flexible envelope member 48, FIGS. 1, 5A, and 5B-, whichencapsulates the respective bottom bar bag and envelope members 44, 45,as illustrated. The outer envelope 48 may also be formed of the samematerial as the bag members 44 and/or the curtain 22. Still further, asshown in FIGS. 5A and 5B, the outer envelope 48 is, preferably, alsosuitably secured to opposite sides of the curtain 22 by a suitableadhesive applied to opposed envelope edge portions 48 a and 48 b, forexample.

[0038] Referring further to FIGS. 5A and 5B, the door curtain 22 is alsoprovided, adjacent its bottom edge 22 e, with lateral stiffening meanscomprising plural end to end connected elongated and relatively thin,somewhat elastically deflectable metal or plastic links 47 which aresecured to each other at their adjacent ends by additional rivets 51 andbacking grommets 51 a to provide a chain like structure extending acrossthe curtain 22 from one lateral side edge to the other. The stiffeningmeans provided by the links 47 resists lateral deflection of the curtain22 out of its normal plane P, FIG. 2, when the curtain is in a doorclosed position. However, if the bottom bar assembly 42 encounters anobstacle as the curtain 22 moves generally in plane P toward its closedposition, the links 47 will pivot with respect to each other to allowthe curtain to flex in a vertical direction or within plane P toaccommodate the obstacle and prevent damage to the curtain or theobstacle. The links 47 are operable to pivot about the central axes ofthe respective pivot connections between each link as provided by therespective rivet and backing grommet assemblies 51, 51 a. In this waythe curtain 22 is operable to resist deflection due to air pressuredifferentials or so called windloads at its bottom edge while beingcapable of deflection in plane P. The interconnected links 47 arepreferably disposed within outer envelope 48, as shown.

[0039] Referring now to FIGS. 1, 2 and 8, opposite side edges 22 c and22 d of the curtain 22, FIG. 1, are guided for movement between thefloor 28 a and the roller or drum 24 by spaced apart somewhat channelshaped guide tracks 54 and 56, FIG. 8, which are suitably secured,respectively, to the members 30 and 32. The guide tracks 54 and 56 maybe identical and are preferably formed-as folded, roll formed orextruded metal members. By way of example, as shown in FIG. 8, the guidetrack 54 includesh a web 54 a and opposed flanges 54 b and 54 c whichare provided with curved reentrant distal ends 54 d and 54 e formingrespective hooks or the like and providing a reduced width slot 54 f.The guide track 56 includes corresponding substantially identicalfeatures which are identified by numerals 56 a through 56 f.

[0040] The slots 54 f and 56 f are operable for receiving the curtain 22as well as opposite ends of plural spaced apart elastically bendablecombination curtain stiffening struts and windlock members 58, see FIGS.1 and 8. The respective strut and windlock members 58 are characterizedby oppositely facing combination strut and windlock parts 60, FIG. 8,which are secured to each other from opposite sides of the curtain 22,with the curtain disposed therebetween, by suitable spaced apartthreaded fastener assemblies 62, as shown in FIGS. 7 and 8. In oneembodiment of the invention each of the combination strut and windlockparts 60 comprises an elongated member, preferably integrally formed ofglass fiber reinforced plastic and having a substantially planar surface64 on one side thereof, FIG. 10. Opposed elongated bosses 66 and 68 areformed and disposed on opposite sides of a recessed portion 70, see FIG.7 also. The bosses 66 and 68 are also intersected adjacent one end by atransverse recess 72 which also intersects the recess 70 to provideshort boss portions 66 a and 68 a, FIG. 7. Boss portions 66 a and 68aform surfaces 66 b and 68 b which are coplanar and extend normal to thesurfaces 64, respectively, of the opposed strut and windlock parts 60.As also shown in FIG. 8, the bosses 66 and 68 are relieved gradually atsurfaces 66 e and 68 e to provide sufficient clearance for the guidetrack distal ends 56 d and 56 e so as to not interfere with the normalmovement of the curtain 22 as it moves between open and closed positionsguided by the guide tracks 54 and 56.

[0041] Referring further to FIGS. 7, 8, and 9, the opposite end of theeach of the strut and windlock parts 60 is also provided with atransverse recess 76 leaving short projections or boss portions 66 f and68 f, respectively. As shown in FIGS. 7 and 9, the boss portions 66 fand 68f are also delimited by surfaces 66 g and 68 g which are inclinedat an angle of about thirty degrees to the surfaces 64, respectively.The bosses 66 and 68 are also relieved at sloping surfaces 66 h and 68 hto provide clearance for the hook-like flange distal ends 54 d and 54 eof the guide track 54, as shown in FIG. 8.

[0042] The configuration of the combination curtain stiffening strut andwindlock members 58 is advantageous. In situations where the doorcurtain 22, in the closed position, is impacted by a vehicle, such as afreight truck, or is subject to extreme windloads, the curtain 22 willbe relieved to prevent damage thereto or to the guide tracks 54 and 56by allowing the curtain side edge 22 c to pull out of the channel formedby the guide track 54 through the slot 54 f formed between the flangedistal ends 54 d and 54 e. However, the opposite side edge 22 d of thecurtain 22 will remain in the channel formed by the guide track 56. Inthis way the forces acting on the curtain may be relieved withoutdamaging the curtain 22 while at the same time the curtain is notentirely released from engagement with the door frame formed by theguide tracks and the frame members 30 and 32.

[0043] Referring to FIGS. 11 and 12, there is illustrated thecooperation between the guide tracks 54 and 56 and the respectiveopposite ends of the combination strut and windlock members 58 undersubstantial deflection of the strut and windlock members as aconsequence of occurrences of the type described above. As shown in FIG.11, thanks to the configuration of the boss portions 66 f and 68 f,including the sloped or inclined surfaces 68 g and 66 g of therespective strut members 58, in response to deflection of the curtain 22and the strut members of about thirty degrees from the plane P of anundeflected curtain, the flanges 54 b and 54 c of guide track 54 willelastically deflect to allow the ends of the strut members 58 whichinclude the boss portions 66 f and 68 f to escape from the guide trackto prevent damage to the curtain or to the combination strut andwindlock members. Forces acting on the curtain 22 and the combinationstrut and windlock members 58 causing deflection of same somewhat lessthan about thirty degrees will not result in the strut and windlockmembers exiting the guide track 54.

[0044] Moreover, as shown in FIG. 12, elastic deflection of the strutand windlock members 58 and the curtain 22 in a range of up to andexceeding about thirty-five to forty degrees will not result in theopposite end of each strut and windlock member exiting the guide track56, thanks to the configuration of the surfaces 66 b and 68 b andengagement thereof with the reentrant or hook-like flange distal ends 56d and/or 56 e. Accordingly, by configuring the strut and windlockmembers 58 as described above, the curtain edge 22 c may exit the guidetrack 54 while the curtain edge 22 d remains in the channel shaped slotof the guide track 56. In this way the door assembly 20 may be subjectedto impacts from various objects or subjected to severe air pressuredifferentials or “windloads” from either side of the door curtain 22while reacting to relieve the forces causing such deflection withoutresulting in the curtain being completely disengaged from the guidestructure provided by the tracks 54 and 56.

[0045] Referring now to FIG. 6, in order for the strut and windlockmembers 58 to be reinserted in the guide track 54 with the door 20 inthe closed position, that is with the curtain 22 substantially unrolledfrom drum 24, the drivemotor unit 38 is operated to begin raising thecurtain by rotating the roller or drum 24 to wind the curtain thereon.As shown in FIG. 6, the guide track 54 is provided with a recapture slot55, preferably formed by bending a portion of the flange 54 b away fromthe flange 54 c as shown at 54 h to create the recapture slot 55 andprovide a guide surface for recapturing within the guide track the endsof respective strut members 58 which have exited therefrom. This actionwill occur as the curtain 22 is reeled onto the drum 24. In this regardthe flange portion 54 h is formed on the guide track 54 near the upperend thereof, as indicated in FIGS. 3 and 6. As further shown in FIG. 6,in the arrangement where the angle frame member 30 is used to supportthe guide track 54 and is provided with opposed flanges 30 a and 30 b,the flange 30 a is cut away and deflected to form a guide surface 30 cand a recapture slot 57. The guide surfaces 54 h and 30 c are suitablyaligned to allow the ends of the strut and windlock members 58, whichinclude the boss portions 66 f and 68 f, to move through the slots 57and 55 to be recaptured within the track 54. In the arrangement of FIG.6 it is anticipated that the curtain edge 22 c will need to bereinserted from only one side of the doorway 26, hence the provision ofa single slot 55 and guide surface 54 h. However, a part of track flange54 c may also be configured to form a guide for recapture of the curtainedge 22 c and strut end portions if the curtain 22 was forced to exitthe guide track 54 in the opposite direction.

[0046] Referring briefly to FIG. 10, a cross section of theconfiguration of the main portions of the bosses 66 and 68 isillustrated wherein surfaces 67 and 69 on the respective bosses areinclined in opposite directions with respect to each other and theplanar surface 64 and are operable to eliminate any sharp edges whichmay form a wear point as the strut and windlock members 58 are woundonto the drum 24 along with the curtain 22. The inclined surfaces 67 and69 also reduce the cross sectional thickness of the bosses 66 and 68sufficiently to minimize any bulging effect of the strut and windlockmembers 58 as they are rolled onto and off of the drum 24. As shown inFIG. 3, the drum 24 is generally aligned tangentially with the upperends of the guide tracks 54 and 56 to facilitate rolling the curtain 22onto and off of the drum.

[0047] The construction and operation of the door assembly 20 isbelieved to be readily understandable from the foregoing description.However, briefly, the curtain 22 is guided for movement between open andclosed positions by the guide tracks 54 and 56 since the opposite endsof the strut and windlock members 58 slide freely in the slots 54 f and56 f formed by the guide track members. The weighted soft bottom barassembly 42 facilitates maintaining proper tension in the curtain 22 asit is moved between door open and door closed positions and conformsreadily to any obstruction which may intrude into the doorway 26 whenthe door curtain is being moved toward a closed position. The specificconfiguration of the bottom bar assembly 42 and the curtain stiffeninglinks 47 are advantageous, as pointed out hereinabove.

[0048] Of course, if a vehicle or other object impacts the curtain 22 inits closed position or the curtain is subjected to substantialwindloads, the strut and windlock members 58, together with the curtain,will elastically deflect substantially until the strut and windlockmembers are deflected to the degree indicated in FIG. 11, at which timethe ends of the strut and windlock members will exit the guide track 54to relieve the forces acting thereon. The strut and windlock members 58may then be recaptured by rotating the drum 24 to reel the curtain 22thereon at least until the strut and windlock members 58 which haveexited the track 54, and also have possibly been deflected past theflange 30 a, are recaptured.

[0049] Referring now to FIGS. 13, 14, 15 and 16, portions of a modifieddoor assembly 20 a in accordance with the invention are illustrated. Thedoor assembly 20 a is substantially like the door assembly 20 except forthe features described hereinbelow. As shown in FIGS. 13 and 14, thedoor assembly 20 a includes one or more combination strut and windlockmembers 88 made up of opposed strut parts 90 which are each providedwith a planar surface 92 and between which is sandwiched the curtain 22.The strut parts 90 are secured together with the curtain 22 disposedtherebetween by suitable fastener assemblies 62, as shown in FIG. 14.The strut parts 90 may also be formed of elastically bendable glassfiber reinforced plastic and include longitudinally extending spacedapart boss portions 94 and 96 similar to the boss portions 66 and 68 ofthe strut parts 60.

[0050] The strut parts 90 are each provided with separate windlockprojections or boss parts 98 and 100, similar in some respect to theboss portions 66 a, 68 a and 66 f, 68 f of the strut members 58. Thewindlock boss parts 98 and 100 are formed as separate members,preferably of a wear resistant, somewhat self lubricating plastic, suchas Nylon, and are secured to the assembly forming the strut member 88 bysuitable threaded fastener assemblies 102, respectively, see FIGS. 15and 16 also. The fastener assemblies 102 are disposed in suitablerecesses 99 and 101, see FIG. 14, of the respective windlock boss parts98 and 100. As further shown in FIGS. 13, 14, and 15, each of the bossparts 98 includes a planar surface 98 a formed thereon extendinggenerally normal to the surface 92 and adapted to engage the reentrantedge or flange end portions 54 d or 54 e of the guide track 54, forexample, to prevent the end of the strut member 88 disposed in the guidetrack 54 from exiting the track, as shown in FIG. 15, in particular.With respect to the door assembly 20 a, the assembly has been modifiedsuch that the side edge 22 c of curtain 22 will be retained in guidetrack 54 while the curtain side edge 22 d and the combination strut andwindlock members 88 may exit from the guide track 56, as will beexplained in further detail herein.

[0051] Referring further to FIGS. 13, 14 and 16, the windlock boss parts100 are provided with opposed inclined surfaces 100 a and 100 b, asshown in the drawing figures, which surfaces are inclined with respectto the surface 92 in such a way that the surfaces 100 a or 100 b willengage the reentrant distal edge or flange end portions 56 d or 56 e ofguide track 56 to deflect or spread the guide track flanges 56 b and 56c sufficiently to allow the curtain side edge 22 d and the strut member88 to exit the guide track 56, as shown in FIG. 16. Accordingly, byproviding inclined surfaces 100 a and 100 b on each of the windlock bossparts 100, the end of the strut member 88 which includes the windlockboss parts 100 may exit the guide track 56 smoothly without undue stresson the windlock boss parts which would tend to damage these parts and/orthe guide track 56. However, as with the door assembly 20, thecombination strut and wihdlock members 88 will not exit the guide track56 until these strut members undergo substantially the amount ofdeflection from the plane P as previously described.

[0052] Referring now to FIG. 17, a modified curtain and strut recapturearrangement is provided for the door assembly 20 a, as shown. Forexample, the guide track 56 may be shortened somewhat from thearrangement shown in FIGS. 1 and 3 to provide for disposition of acurtain side edge recapture assembly 110. A curtain side edge recaptureassembly 110 is shown mounted adjacent and directly above a top edge 56hof guide track 56 and suitably secured to the support member 32. Thecurtain recapture assembly 110 includes a generally flat plate supportmember 112 adapted to be suitably secured to the support member 32 byfasteners, not shown in FIG. 17. The support member 112 supports opposedguide flanges 114 and 116 which are mirror image parts and includeopposed outwardly diverging upper guide portions 114 a and 116 a forguiding the curtain 22 as it is reeled onto and off of a support drum orroller 24, also not shown in FIG. 17.

[0053] The guide flange members 114 and 116 also include inclined flangeparts 114 b and 116 b which extend downwardly and outwardly with respectto each other and with respect to the opposed flanges of the guide track56 for guiding the ends of the strut members 88 which include thewindlock boss parts 100 back into the slot 56 f of the guide track 56 ifthe curtain 22 should be pulled out of the guide track in the mannerpreviously described. However, the curtain recapture assembly 110 alsoincludes opposed elastically deflectable plate members 114 c and 116 cwhich are suitably secured at their lower ends to supports 117 and 118each being connected to the support plate 112. The upper ends 114 c′ and116 c′ of the guide members 114 c and 116 c are unsupported and themembers 114 c and 116 c are operable to deflect inward, one toward theother, to allow the ends of the strut members 88 to be guided by theguide members 114b and 116 b back into the guide track 56. Thedeflectable guide members 114 c and 116 c are, however, normallyoperable to be in their positions as shown in FIG. 17 to guide thecurtain edge 22 d and the strut members 88 within the guide track slot56 f during normal operation of the door assembly 20 a. A mirror imagepart of the recapture assembly 110 may be provided on the opposite sideof the door assembly 20 a if the curtain 22 is to be allowed to exit theguide track 54 instead of the guide track 56.

[0054] Referring now to FIGS. 18 and 19, an alternate embodiment of asoft bottom bar assembly is illustrated and generally designated bynumeral 122. Bottom bar assembly 122 includes a flexible outer envelope48 secured to a curtain 22 in the same manner as for the embodimentillustrated in FIGS. 5A and 5B. However, the bottom bar assembly 122also includes an elongated, somewhat flexible obstruction detector 124which may be of a type commercially available, such as from Miller Edge,Inc. of Jennersville, Pa. As shown in FIGS. 18 and 19, the bottom barassembly 122 further includes plural weight members comprising flexiblebags 44a, similar to the bags 44, and disposed within respective innerenvelope members 45 a generally in the same manner that the bags 44 aresupported in and by the envelope members 45. The bags 44 a are disposedon opposite sides of a web part 125 of the obstruction detector member124 and contain suitable quantities of particulate material 46,respectively. The envelopes 45 a and the web 125 of the obstructiondetector 124 are secured by rivet assemblies 51, 51 a to the curtain 22adjacent its bottom edge 22 e as shown in FIGS. 18 and 19.

[0055] The outer envelope 48 encapsulates or covers the aforementionedcombination of the obstruction detector 124 and the bag and innerenvelope assemblies 44 a, 45 a. Still further, as shown in FIG. 19, thecurtain 22, for the arrangement of a bottom bar assembly 122, may alsobe stiffened against lateral deflection out of its plane P by thestiffening means formed by the interconnected links 47 in the samemanner as described hereinabove.

[0056] In addition to the materials and items specified herein,conventional engineering materials may be used for constructing the doorassemblies 20 and 20 a. The fabrication thereof is believed to bereadily achievable by those skilled in the art based on the foregoingdescription and a further detailed description is not believed to benecessary to practice the invention.

[0057] Although preferred embodiments of a rollup door assembly inaccordance with the invention have been described in detailhereinbefore, those skilled in the art will recognize that varioussubstitutions and modifications may be made to the invention withoutdeparting from the scope and spirit of the appended claims,.

What is claimed is:
 1. In a door comprising a flexible curtain closuremember having a transverse bottom edge and opposed side edges; spacedapart guide tracks for guiding the side edges of said curtain formovement between open and closed positions of said door; and opposedwindlock members supported on said curtain adjacent opposite side edgesthereof and adapted for movement within said guide tracks for retainingsaid curtain edges in said guide tracks, at least one of said windlockmembers being configured for response to a predetermined deflection ofsaid curtain to exit one of said guide tracks while an opposite one ofsaid windlock members is configured to retain said curtain in anopposite one of said guide tracks whereby said curtain is relieved offorces acting thereon by exiting said one of said guide tracks along oneof said side edges.
 2. The door set forth in claim 1 wherein: said atleast one windlock member includes surfaces formed thereon forengagement with said one of said guide tracks in response to deflectionof said curtain and operable to provide for said at least one windlockmember to exit said one of said guide tracks at a predetermined amountof said deflection.
 3. The door set forth in claim 2 wherein: pluralwindlock members are secured to said curtain and are spaced apart alongsaid side edges, respectively.
 4. The door set forth in claim 2 wherein:said opposite one of said windlock members includes surfaces formedthereon engageable with said opposite one of said guide tracks to retainsaid curtain in said opposite one of said guide tracks.
 5. The door setforth in claim 4 wherein: said windlock members are disposed on oppositeends of an elongated elastically deflectable strut secured to saidcurtain.
 6. The door set forth in claim 5 wherein: said strut comprisesopposed strut parts secured to each other and to said curtain with saidcurtain disposed between said strut parts.
 7. The door set forth inclaim 6 wherein: each of said strut parts includes a planar surface andopposed boss portions opposite said planar surface.
 8. The door setforth in claim 7 wherein: said boss portions include surfaces inclinedwith respect to said planar surface to minimize wear and bulging of saidcurtain when being rolled onto and off of a drum.
 9. The door set forthin claim 5 wherein: said windlock members are formed as separate partsand are removably secured to said strut by fastener means, respectively.10. The door set forth in claim 1 including: a bottom bar assemblysecured to said curtain at said bottom edge, said bottom bar assemblycomprising a plurality of flexible bag members filled with particulatematerial and secured to said curtain adjacent said bottom edgesubstantially side by side across a major portion of said bottom edge.11. The door set forth in claim 10 including: an obstruction detectorsecured to said curtain at said bottom edge and adjacent said flexiblebag members.
 12. The door set forth in claim 1 including: curtainstiffening means secured to said curtain adjacent said bottom edge forstiffening said curtain against lateral deflection while allowingdeflection of said curtain substantially vertically within a normalplane of said curtain.
 13. The door set forth in claim 12 wherein: saidstiffening means comprises interconnected link members extending acrosssaid curtain adjacent said bottom edge and secured to said curtain,respectively.
 14. The door set forth in claim 10 wherein: said bottombar assembly includes a flexible outer envelope member disposed oversaid bags and secured to said curtain.
 15. The door set forth in claim 1including: a drive motor unit drivingly connected to a drum for rollingsaid curtain there onto to open said door, including a right angle gearreduction unit and an output shaft adapted to be connected to a distalshaft part of said drum in driving engagement therewith, said drivemotor unit being mountable on a frame member of said door.
 16. The doorset forth in claim 1 including: a slot formed in said one of said guidetracks and a guide surface disposed adjacent said slot for recapturingsaid at least one windlock member in said one of said guide tracks. 17.The door set forth in claim 1 including: a windlock member recaptureassembly disposed adjacent said one of said guide track at one endthereof and including at least one recapture guide for guiding awindlock member for recapture within said one of said guide tracks. 18.The door set forth in claim 17 including: opposed recapture guides forguiding a windlock member and a curtain edge for recapture within saidone of said guide tracks from opposite sides thereof.
 19. The door setforth in claim 18 including: at least one deflectable guide memberassociated with recapture assembly and forming a guide path coincidentwith said one of said guide tracks during normal movement of a curtainedge within said one of said guide tracks, said deflectable guide memberbeing operable to deflect in response to movement of said curtain edgeand said windlock member for reinsertion of said curtain edge withinsaid one of said guide tracks.
 20. A flexible curtain door for forming aclosure over an opening comprising: an elongated flexible curtainincluding a transverse bottom edge and opposed side edges; a door frameincluding opposed side edge guide tracks comprising members formingopposed slots for receiving side edges of said curtain therein; andplural spaced apart elastically deflectable combination stiffening strutand windlock members secured to said flexible curtain at spaced apartpoints thereon, said combination strut and windlock members includingopposed windlock parts disposed in said guide tracks and adapted toretain said curtain in said guide tracks, said windlock parts in one ofsaid guide tracks being configured to release said curtain from said oneside track, and said windlock parts disposed in the other guide trackbeing configured to retain said curtain in said other guide track inresponse to forces acting to displace said curtain from said guidetracks.
 21. The door set for in claim 20 including: means forming arecapture slot for reinserting said windlock parts within said one guidetrack in response to movement of said curtain with respect to saidframe.
 22. In a rollup door comprising a flexible curtain closure memberhaving a transverse bottom edge and opposed side edges, said curtainbeing adapted to be wound on and unwound from a rotatable drum; spacedapart guide tracks for guiding said side edges of said curtain formovement between open and closed positions of said door; at least onecombination strut and opposed windlock members connected to saidcurtain, said windlock members being disposed adjacent said opposed sideedges and adapted for movement within said guide tracks, respectively,for retaining said curtain in said guide tracks, one of said windlockmembers being responsive to a predetermined deflection of said curtainto exit one of said guide tracks while the other of said windlockmembers retains said curtain in the opposite one of said guide trackswhereby said curtain is relieved of forces acting thereon by exitingsaid guide track along said one side edge of said curtain; and said onewindlock member includes surfaces formed thereon for engagement with atleast one of opposed flanges of said one guide track for deflecting saidone flange in response to deflection of said curtain to provide for saidone side edge to exit said one guide track
 23. A flexible curtain doorfor forming a closure over an opening comprising: an elongated flexiblecurtain including a transverse bottom edge and opposed side edges;opposed side edge guide members for guiding said side edges of saidcurtain; and a flexible bottom bar assembly secured to said curtain atsaid bottom edge and comprising a plurality of flexible bags filled withparticulate material and secured to said curtain adjacent said bottomedge substantially side by side across at least a portion of said bottomedge.
 24. The door set forth in claim 23 wherein: said bottom barassembly includes a flexible outer envelope member disposed over saidbags.
 25. The door set forth in claim 23 including: curtain stiffeningmeans secured to said curtain adjacent said bottom edge for stiffeningsaid curtain against lateral deflection while allowing deflection ofsaid curtain substantially within a normal plane of said curtain. 26.The door set forth in claim 25 wherein: said stiffening means comprisespivotally interconnected link members extending across said curtainadjacent said bottom edge and secured to said curtain, respectively. 27.The door set forth in claim 23 including: an obstruction detectorsecured to said curtain at said bottom edge and adjacent said flexiblebags.